Hydrocarbon reservoirs are being discovered and developed offshore in deep water tracts. Offshore drilling platforms may be anchored in water depths of more than 9,200 feet or dynamically positioned in water depths greater than 10,000 feet. Offshore wells are being drilled to depths that exceed 34,000 feet.
Wireline operations are often conducted on offshore platforms. Wireline units, also known as logging units, may be used to survey hydrocarbon wells to determine their geological, petrophysical, or geophysical properties. An electronic measuring instrument or logging tool is lowered into the well bore on a steel cable known as a wireline. The logging tool takes measurements and transmits them to the well surface through electronic circuits in the wireline. Other downhole tools, besides logging tools, may be used on wireline. Adapted with such other tools, wireline may be used to perforate pipe or casing, recover pipe or tools, run casing, run lines, run landing string, and work over a well.
In deep water the wireline must be run to a greater depth. As the wireline tool and wireline are lowered into the well, the line weight increases as the depth of the tool is increased. Eventually, the tensile strength of the wireline is reached. When this happens, the wireline either breaks or the tool and wireline cannot be pulled out of the well. This failure would cause catastrophic equipment loss, unnecessary recovery costs, and delay operations.
Because reservoirs are being discovered at deeper water depths and wells are being drilled to deeper depths, the need exists for wireline operations that function reliably, effectively, and without failure at ever increasing depths.